THE AMAZING GIRAFFE

There are many impressive things about an 18-foot giraffe, the tallest of all land animals. Among these is its ability to run 34 miles per hour, sleep about 30 minutes per day, and to go weeks without drinking. However, one of the most remarkable features of the giraffe is its circulatory system. (The scientific information in this article was taken from the January 2009 issue of “Reason and Revelation.”

The giraffe’s brain is eight feet higher than its head. He must have an enormous heart to pump blood hard enough to travel that distance against gravity. It must maintain blood pressure as long as the giraffe’s neck is vertical. This amazing animal is equipped with a thick-walled, 20 pound heart that is able to pump blood eight feet high, creating blood pressure that is about twice that of any other large mammal and as much as three times that of the average human.

What about when the giraffe lowers its head several feet below its heart? What happens to the blood the heart normally pumps to the brain? How does he keep from having brain bleeds or from feely dizzy and passing out every time he bends down and raises back up? The giraffe has valves in its jugular veins that help control how much blood gets to the brain when it has its head lowered. Working with these valves is a network of blood vessels that controls the flow of blood into the head. When the head is raised, the same network counters the danger of blackouts from reduced blood pressure.

Then there is the matter of the lower extremities. Since giraffes stand on their feet most of the day and have such high blood pressure, how do they keep their lower extremities from pooling and swelling with blood? They have a tight sheath of thick skin over their lower limbs that maintains high extravascular pressure. Leakage from the capillaries in the giraffe’s legs is prevented by the pressure of tissue fluid outside the cells. In addition, the walls of the arteries are thicker than those in any other mammal.

Let’s review. The giraffe has:
 A complex pressure regulation system.
 Unique valves that prevent over-pressure when it lowers its head.
 A network of blood vessels that helps stabilize blood pressure as the giraffe moves its neck up and down.
 A heart powerful enough to send an adequate amount of blood eight feet upwards against gravity.
 Arteries in the lower parts of its body thick enough to withstand the high blood pressure.
 Skin tight enough to force blood back upward and keep capillaries in its lower extremities from bursting.
 Oversized lungs that compensate for the volume of dead air in its 10 foot long trachea.
And all of this happened by chance and almost simultaneously? Did the large heart evolve before or after the long neck? When did the valves and blood vessels enter the picture? How many “evolving” giraffes died from blood loss due to bursting vessels in their legs because the blood pressure was too great?

It is indeed true that “The heavens declare the glory of God; And the firmament shows His handiwork” (Psalm 19:1). It is not mankind alone that is “fearfully and wonderfully made” (Psalm 139:14). In other aspects of life we understand that design demands a designer. Why is it that so many have such a hard time accepting the fact that this universe and everything in it was created by a marvelous, powerful God? It is no wonder the psalmist says, “The fool has said in his heart, “There is no God” (Psalm 14:1).
--Lamar